[2] Most notably it features an exhibition of items related to James Watt, the Greenock-born inventor, a Mummy Cartonnage from Herakleopolis Magna and a collection of British and Scottish art.

"[5] The Society sent a report to local ship owners and masters to generate interest in the museum's collection in the hope of receiving donations.

[6] The new building was completed by 3 November 1876, but James McLean was unable to attend the opening due to ill health (although he still managed to visit and inspect the museum's contents), later dying in January of the next year.

Until 1914 the McLean Museum received continuing donation from the Egypt Exploration Society, which provided the museum with many items for its Egyptology collection, including a Mummy Cartonnage from Herakleopolis Magna and the temple stone from the Great Temple of Bast at Bubastis.

[4] In 2016, Inverclyde Council closed the McLean Museum and Watt Library complex in order to undertake a £2 million refurbishment.

The Council invested £1.8 million towards the refurbishment work alongside a £287,000 grant from Historic Environment Scotland.